diff --git a/src/kernel/desktop-comm.c b/src/kernel/desktop-comm.c
index dc32d4ac..8ce98eb5 100644
--- a/src/kernel/desktop-comm.c
+++ b/src/kernel/desktop-comm.c
@@ -2445,6 +2445,11 @@ static LRESULT DesktopWinProc (HWND hWnd, UINT message,
         return dskUnregisterMsgQueue ((MSGQUEUE*)lParam);
 #endif
 
+    /* Since 5.0.0 */
+    case MSG_CALC_POSITION:
+        dskCalculateDefaultPosition (0, (CALCPOSINFO*)lParam);
+        return 0;
+
     case MSG_IME_REGISTER:
         return dskRegisterIMEWnd ((HWND)wParam);
 
diff --git a/src/kernel/desktop-procs.c b/src/kernel/desktop-procs.c
index f4abb796..5f04daba 100644
--- a/src/kernel/desktop-procs.c
+++ b/src/kernel/desktop-procs.c
@@ -801,7 +801,7 @@ static intptr_t cliFreeZOrderMaskRect (PMAINWIN pWin)
     req.data = &info;
     req.len_data = sizeof(ZORDERMASKRECTOPINFO);
 
-    if ((ret = ClientRequest (&req, &ret, sizeof (intptr_t))) < 0) {
+    if (ClientRequest (&req, &ret, sizeof (intptr_t)) < 0) {
         return -1;
     }
     return ret;
@@ -3040,7 +3040,8 @@ static int cliRegisterHookWin (HWND hwnd, DWORD flags)
     req.id = REQID_REGISTERHOOK;
     req.data = &info;
     req.len_data = sizeof (REGHOOKINFO);
-    ClientRequest (&req, &retval, sizeof (int));
+    if (ClientRequest (&req, &retval, sizeof (int)) < 0)
+        return -1;
 
     return retval;
 }
@@ -3060,11 +3061,29 @@ static int cliUnregisterHookWin (HWND hwnd)
     req.id = REQID_REGISTERHOOK;
     req.data = &info;
     req.len_data = sizeof (REGHOOKINFO);
-    ClientRequest (&req, &retval, sizeof (int));
+    if (ClientRequest (&req, &retval, sizeof (int)) < 0)
+        return -1;
 
     return retval;
 }
 
+static int cliCalculateDefaultPosition (CALCPOSINFO* info)
+{
+    RECT retrc;
+    REQUEST req;
+
+    assert (!mgIsServer);
+
+    req.id = REQID_CALCPOSITION;
+    req.data = info;
+    req.len_data = sizeof (CALCPOSINFO);
+    if (ClientRequest (&req, &retrc, sizeof (RECT)) < 0)
+        return -1;
+
+    info->rc = retrc;
+    return 0;
+}
+
 #if 0   /* Since 5.0.0, deprecated */
 static HOOKINFO keyhook = {0, HWND_NULL, 0};
 static HOOKINFO mousehook = {0, HWND_NULL, 0};
@@ -4652,6 +4671,16 @@ static LRESULT DesktopWinProc (HWND hWnd, UINT message,
         return dskUnregisterMsgQueue ((MSGQUEUE*)lParam);
 #endif
 
+    /* Since 5.0.0 */
+    case MSG_CALC_POSITION:
+        if (mgIsServer) {
+            dskCalculateDefaultPosition (0, (CALCPOSINFO*)lParam);
+            return 0;
+        }
+        else
+            return cliCalculateDefaultPosition ((CALCPOSINFO*)lParam);
+        break;
+
     case MSG_IME_REGISTER:
         if (mgIsServer)
             return srvRegisterIMEWnd ((HWND)wParam);
diff --git a/src/kernel/desktop.c b/src/kernel/desktop.c
index bb135ee9..46858945 100644
--- a/src/kernel/desktop.c
+++ b/src/kernel/desktop.c
@@ -4853,3 +4853,137 @@ static inline int post_quit_to_all_message_threads (void)
 }
 
 #endif  /* defined _MGHAVE_VIRTUAL_WINDOW */
+
+/* Since 5.0.0 */
+static int dskCalculateDefaultPosition (int cli, CALCPOSINFO* info)
+{
+    ZORDERINFO* zi;
+    ZORDERNODE* nodes;
+    DWORD zt_type = ZOF_TYPE_NULL;
+    int level, first;
+
+    zi = get_zorder_info (cli);
+    nodes = GET_ZORDERNODE(zi);
+
+#ifdef _MGRM_PROCESSES
+    if (cli == 0)
+        zt_type = ZOF_TYPE_GLOBAL;
+    else
+#endif
+    switch (info->ex_style & WS_EX_WINTYPE_MASK) {
+    case WS_EX_WINTYPE_TOOLTIP:
+        zt_type = ZOF_TYPE_TOOLTIP;
+        break;
+
+#ifdef _MGRM_PROCESSES
+    case WS_EX_WINTYPE_GLOBAL:
+        zt_type = ZOF_TYPE_GLOBAL;
+        break;
+#endif
+
+    case WS_EX_WINTYPE_SCREENLOCK:
+        zt_type = ZOF_TYPE_SCREENLOCK;
+        break;
+
+    case WS_EX_WINTYPE_DOCKER:
+        zt_type = ZOF_TYPE_DOCKER;
+        break;
+
+    case WS_EX_WINTYPE_LAUNCHER:
+        zt_type = ZOF_TYPE_LAUNCHER;
+        break;
+
+    case WS_EX_WINTYPE_HIGHER:
+        zt_type = ZOF_TYPE_HIGHER;
+        break;
+
+    default:
+        zt_type = ZOF_TYPE_NORMAL;
+        break;
+    }
+
+#ifdef _MGRM_PROCESSES
+    /* check the special types */
+    switch (zt_type) {
+    case ZOF_TYPE_TOOLTIP:
+        if (zi->first_tooltip > 0 &&
+                nodes [zi->first_tooltip].cli != cli) {
+            zt_type = ZOF_TYPE_HIGHER;
+        }
+        break;
+
+    case ZOF_TYPE_GLOBAL:
+        if (cli != 0) {
+            zt_type = ZOF_TYPE_HIGHER;
+        }
+        break;
+
+    case ZOF_TYPE_SCREENLOCK:
+        if (zi->first_screenlock > 0 &&
+                nodes [zi->first_screenlock].cli != cli) {
+            zt_type = ZOF_TYPE_HIGHER;
+        }
+        break;
+
+    case ZOF_TYPE_DOCKER:
+        if (zi->first_docker > 0 &&
+                nodes [zi->first_docker].cli != cli) {
+            zt_type = ZOF_TYPE_HIGHER;
+        }
+        break;
+
+    case ZOF_TYPE_LAUNCHER:
+        if (zi->first_launcher > 0 &&
+                nodes [zi->first_launcher].cli != cli) {
+            zt_type = ZOF_TYPE_NORMAL;
+        }
+        break;
+    }
+#endif  /* defined _MGRM_PROCESSES */
+
+    level = ZOF_TYPE_TO_LEVEL_IDX (zt_type);
+    first = zi->first_in_levels[level];
+
+#ifdef _MGSCHEMA_COMPOSITING   /* not defined _MGSCHEMA_COMPOSITING */
+    DO_COMPSOR_OP_ARGS (calc_mainwin_pos,
+            __mg_get_layer_from_zi(zi), zt_type, first, info);
+#else   /* defined _MGSCHEMA_COMPOSITING */
+    /* give a default size first */
+    if (IsRectEmpty (&info->rc)) {
+
+        info->rc.left = 0;
+        info->rc.top = 0;
+        if (info->ex_style & WS_EX_DIALOGBOX) {
+            info->rc.right = g_rcScr.right / 2;
+            info->rc.bottom = g_rcScr.bottom / 3;
+        }
+        else {
+            info->rc.right = g_rcScr.right / 2;
+            info->rc.bottom = g_rcScr.bottom;
+        }
+    }
+
+    if (info->ex_style & WS_EX_DIALOGBOX) {
+        // center the window vertically and horinzontally
+        int width = info->rc.right - info->rc.left;
+        int height = info->rc.bottom - info->rc.top;
+
+        OffsetRect (&info->rc, (g_rcScr.right - width) >> 1,
+                    (g_rcScr.bottom - height) >> 1);
+    }
+    else {
+        if (first == 0) {
+            info->rc.left = 0;
+            info->rc.top = 0;
+        }
+        else {
+            info->rc = nodes[first].rc;
+            OffsetRect (&info->rc,
+                    DEF_OVERLAPPED_OFFSET_X, DEF_OVERLAPPED_OFFSET_Y);
+        }
+    }
+#endif  /* defined _MGSCHEMA_COMPOSITING */
+
+    return 0;
+}
+
diff --git a/src/server/request.c b/src/server/request.c
index da76b2d4..d5deaed8 100644
--- a/src/server/request.c
+++ b/src/server/request.c
@@ -346,11 +346,10 @@ ret:
 static int calc_position (int cli, int clifd, void* buff, size_t len)
 {
     CALCPOSINFO* info = (CALCPOSINFO*)buff;
-    RECT rc = info->rc;
 
-    SendMessage (HWND_DESKTOP, MSG_CALC_POSITION, (WPARAM)info, (LPARAM)&rc);
+    SendMessage (HWND_DESKTOP, MSG_CALC_POSITION, (WPARAM)cli, (LPARAM)info);
 
-    return ServerSendReply (clifd, &rc, sizeof (RECT));
+    return ServerSendReply (clifd, &info->rc, sizeof (RECT));
 }
 
 static int create_cursor (int cli, int clifd, void* buff, size_t len)